Process and means for purifying boiler water



Dec. 23, 1930. R. o. HENszr-:Y

PROCESS AND MEANS FOR PURIFYING BOILER WATER Fiied Nov. 8. 192s INVENTOR HaHa/MEE BY moua', n

ATTORNEYS QN. mwbw n APatented Dec. 23, 1930 l ROY O. HENSZEY, F OCONOMOWOC, WISCONSIN PROCESS AND MEANS FOR PURIFYING BOILER WATER Application filed November My invention relates to a process and means-for purifying boiler water, such as that used in boilers in steam power plants, etc., and it consists in the constructions hereinafter set forth, and the steps to .carry out the invention. The present application is a continuation in part of my pending applications, Serial No. 725,531, filed July 11, 1924, and Serial No. 17,413, filedMarch 21,1925.

The term boiler water is designed to be generic; that is to'say, it is designed to include Water Which is already in the boiler,r

as Well as boiler feed Water, and Water withdrawn from the boiler so long as it is substantially under boiler pressure. It is well known by power plant operators and users of water softening devices that nearlyI every type of Water softener feeds some soluble matter, usually sodium 2o sulphate, into the boiler, where any sulphate hardness appears. Certain types of Water softeners feed to the boiler, in addition, sodium carbonate, wherever other softening devices precipitate carbonates out of the water entirely. Raw untreated water as Well as partially softened Water Will-pass to the boiler impurities that Will precipitate and cause foam, mud or scale.

.In the operation of the ordinary steam boiler plant, Water is continuously fed to the boiler, and nearly pure steam is taken from the boiler, with the result that the soluble salts and other impurities concentrate in the boiler. eral bad effects. First, it causes the priming of the water out of the boiler into the steam line, Where the Water'on evaporating leaves th-e dry, soluble salts. This causes trouble in steam driven machinery and other steam using equipment. Second, it is generally accepted vas a. fact that certain of these soluble salts, particularly sodium -carbonate, causes embrittlement of the steel plates of the boiler. Third, it is a Well known fact that dissolved and suspended gases, such as oxygen, are passed with the boiler feed Water into boilers. These gases cause corrosion and pitting in boilers and steam lines and devices fed with steam from the boiler. Fourth, the precipitated impurities form scale or de- This concentration has sev# s, 1926. serial No. 147,122.

posits on the heating surfaces of the boiler. The pecipitated impurities together with soluble impurities cause fluctuation of Water level in the boiler.

i An object of my invention is to providey a purifying proc-ess by means of which the quantity of .foreign/matter, such as soluble, suspended, or precipitated salts, oil, etc., contained in the boiler, is maintained at a minimum, thereby reducing the formation of scale, foreign deposits, embrittlement, dirty steam and other attendant evils.

A further object of my invention is to provide av purifying process by means of which the boiler feed Water is de-,aerated V A further object of my invention is to provide means for accomplishing the deconcentration and de-aerating Without any appreciable loss of heat, and in` such a manner that the process may be substantially continuous; that is to say, the cle-aerating in one portion of the apparatus may be going on while the deconcentration is proceeding in another portion of the apparatus.

A further object of my invention is to provide a process which may be installed at a relatively low cost and which may be used in connection with any ordinary water softener, and especially with base exchange softeners, to remove the soluble salts delivered by them.

A further object is to make more practical the treatment of Water within ysteam boilers.

A further object of my invention is to provide a means of heat transfer from the with drawn Water to the make-up water and boiler feed water that Will practically prevent scale or deposits in the heat exchanger.

A further object of my invention is to provide a means of heat transfer whereby the condensate returns and other heated boiler feed Water can be used for cooling whereby the cold make-up water will be relieved of part of the cooling of the withdrawn water, thereby increasing the` withdrawal capacity of the means without appreciable loss of heat.

A further object of my invention is to minimize the heat lost in withdrawn Water, and ,to provide means of regulating the withdrawal according to the quantity of makeup Water added to the feed Water system, by using cold make-up Water as a cooling medium in the last stage of cooling.

A further object of my invention is to Withdraw water in proportion to an increase lor decrease in the degree of concentration within the boiler.

A further object of my invention is to provide a means for joining the make-up and returns streams so that they will function best for cooling withdrawn water and at the saine time provide best for de-aerating and otherwise conditioning the water, and regulating the flow of the above mentioned streams of Water.

A further object is to minimize the loss of water permanently Withdrawn from the boiler to accomplish a certain degree of deconcentratioii, by causing the degree of concentration in the permanently withdrawn water to be increased over that in the boiler, by impurities drawn from Within the boiler.

Other objects and advantages will appear in the following specification, and the novel features of the invention will be particularly pointed out in the appended claims.

My invention is illustrated in the accompanying drawings, forming part of this application, in Which The ligure is a diagrammatic view'illustrating one embodiment of my invention.

Referring now to `the drawing, I have shown therein a boiler which I have indicated in general at 1 and Which is provided with a drum 2. Extending from this drum is a pipe 3, which leads to the steam-consuming devices, such as an engine, shown diagrammatically at 4, or a heater, as shown at 5. The condensed steam returns from the heater 5 pass on to a feed water heater 6 by means of the pipe 7, While the exhaust steam frcfni the engine 4 passes to the feed water heater by means of the pipe 8. A boiler feed A pump 9 draws water from the heater 6 and can, discharge it directly into the boiler l through a pipe 10 when the valve 11, which controls this pipe, is open. In ordinary practice, some of the steam which leaves the boiler is not returned to the boiler, and, therefore, provision is made to supply make-up Water to the heater 6 through a pipe 12 leading from a cold water supply pipe 13. The pipe 12 is controlled by a valve 14 which is actuated by a float 15. A by-pass 16, which is controlled by a valve 17, permits of manual control of the Water feed into the heater 6. rlhe the added make-up Water. The impurities fed with the make-up water concentrate in the boiler. If boiler water containing concentrated impurities is withdrawn from the boiler and replaced by comparatively pure makeup water the concentration will be reduced. By a proper exchange of concentrated boiler Water for fresh make-up water the concentration can be reduced to and held at a practically harmless degree. This is accomplislied by niy invention.

Referring again to the drawing, I have shown a pipe made up of sections 18, 18a leadfrom the drinn 2 to the first stage A of a heat intel-changer. The pipe 18, 18a is controlled by a valve 19, and normally this valve is closed. Vater from the boiler, however, may be drawn otl" through the pipe 20, into a settling chainber 21, and from thence passes by the pipe 22 and the pipe 18 to the stage A of the heat interchanger. Valves 20a and 22a are provided for the pipes 20 and 22, respectively.

T he heat interchanger is divided into two sections, A and B, respectively, corresponding to two stages of temperature. Any suitable arrangeinent for interchanging heat may be used.. I have indicated diagraminatically aheat interchanger consisting of exterior pipes which are connected' in series and which have interior pipes running; therethrough. As will be seen from the drawing, the exterior pipes a of the heater A which are connected in series are connected bymeans of a pipe 23 with the pipe 10, a valve'23EL controlling the pipe 23. The pipe 18 is connected with the interior pipes a and the latter are connected with the interior pipes b of the temperature stage B.

At 24 I have shown a pipe leading froni the supply pipe 13 to a water softener 25 through a valve 26. This water softener may be of any suitable type and it is connected by means of a pipe 27 with the exterior pipe b of the low temperature stage B. The latter is connected by a pipe 28 to the make-up storage tank 29. A valve 30 controls communication between the make-up storage tank 29 and the pipe 12.

In order to control the operation of the device automatically, in the manner to be explained later, I may provide the apparatus shown diagrammatically'inear the bottom of the figure. At 31 I have shown a valve for controlling the make-up 4water inlet to the low temperature stage B of the heat interchanger, While a valve 32 controls the withdrawn boiler water outlet from the low temperature stage. These two 'valves may be actuated by a diaphragm 33 in a chamber which communicates by pipes S34-and 35 with the opposite sides of a casing 36 having a diaphragm 37 provided with an orifice 33. The valves 31 and 32 are on a common valve stem 39. This stem may be actuated by a mea-11s p movement of the Heat through the medium. 'of the rod 40, the bell crank lever 41, the link 42, and the lever 43' to which the -stem 39 is connected. The float 15 may also control the va1ve14 through the medium of the link 44 and "the lever 44a. The withdrawn boiler Water outlet 45 from the' low temperature stage of the heat iriterchanger has connected therewith a chamber 1'0 46 in which are electrodes 47 and 48, one of `which is connected with a battery 49 and the other with a solenoid 50 whichv is connected on its opposite side to Vthe'battery. p

` The withdrawn boiler water outlet 45 may 15 also communicate with a 'chamber 51 containing a thermostatic'element 52 arranged to operate ai lever 53 connected with the valve 54. The lever 53 has an extension 55 which may be actuated by the core of the solenoid a 50 to operate as hereinafter described. It

will be understood that the diagrammatic showingis for the urpose of illustration' only and that any suitable forms of these devices might befused without departing from the spirit of the invention. The thermostatic element 52 in chamber 51 could operate a valvein make-up line 27 to increase or decrease the How of make-up as the temperature of the discharge through pipe 4 5 would su rise or fall; the object being toV conserve heat.

A circulatingv pipe system is shown at 18a, 20, and 21a. The boiler Water is withdrawn ,from the boiler drum 2 through pipe 18a and flows thence through valvel 20a, pipe 20,

settling chamber 21 and'thence through pipe 21a back to the boiler. This circulation can be induced by mechanical means, the force due to the circulation within the boiler, or by the fact that the decending water in the pipe l21a may be colder than the water in the boiler. The settling chamber has a larger diameter than the pipes 20 and 21a and therefore some of the suspended matter 'has time to settle down to the bottom-of the chamber,

from which point it is permanently withdrawn from the boiler system' through the pipes 22 and 18. y

y From the foregoing description of the` various parts of the dev1ce,tl1`e operation thereo of ma?)1 be readily understood. Let us assume that t e boiler has been in operation and that the salts or other impuritiesarefbeing con-` centrated withthe apparatus arranged as indicated.' Water from, the' boiler Vcontainingr g i 55 concentrated salts may be drawnoif -throu the'pipe 18a and (the valve 19 being closed and the valves 20a and 22a being open) through thepipe 20, tank21, pipe 22 and then by the pipe 18 through the high' and low G0 temperaturel stages of the heat interchanger,

and may be discharged through the pipe 45.

Ordinarily a greater quantity of water' is withdrawn from the boiler drum'through the pipe 18a lthan is permanently withdrawn CS from the boiler through the pipe 18. The

excess water returns through the pipe 21a to the boiler, after a part of the suspended solids have settle-dto the bottom of the chamber 21, where the lare withdrawn through the pipe 18. By t is -means a small quantity of permanently Withdrawn water can withdrawa relatively large amount of impurities from the boiler. While this is going on, the

`boilerl feed line 10 (the valve 11 being closed and the valves 23a and 11a being open) will cause a flow through the pipe 23, through the high temperature stage A. of the heat interchanger, and back through the pipe 10l into the boiler. Heat from the water passing from the boiler will therefore be transferred to the feed water at the high .temperature stage of the heat interchanger.'

To gain utmost economy and benefit of the invention, it is desirable to withdraw boiler water faster if the concentration is high, and

yslower if the concentration is lower. This.

will effect a saving in water if the concentration is low. It is known that the conductivity of water for an electric current varies with the degree of concentration of saltsin the water. Advantage is taken of thisifact to cause the How of a current of electricity to be varied according to the conductivity of `the boiler water and to use this current for the flow of water permanently withdrawn from the boiler or the blow-oii.V

,Itis also desirable to withdraw boiler water more slowly if the discharge is warm and, to withdraw it .faster if the discharge is cooler. This will eii'ect a saving of heatwhen the eiiluent is warm. In order to effect this, I make use of the thermostatic element 52 inl the ychamber 5 1; When the water in this chamber is warmer, it will cause the thermostatic element to operate, thus, if the thermostatic element elongates, it will'operate the lever 5 3, which controls the valve 54, so as to tend to close, it or to openjtwhen the discharge is cooler.

. It isA also desirable to withdraw boiler'.

water in'proportion to the rate of feeding makewater into the system, because the ratio o the rate of withdrawal to the rateof adding make-up water will approximately control the concentration, especially of soluble salts. The control of the blow-off, "according-to the rate of flow of boiler feed, would not regulate' the concentration, because the quantity 'of'make-up water practically never bears-a fixed ratio to the quantity of boiler feed.

While the water containing the concentrated salts is being discharged from the boiler, cold Water from the supply pipe 13 is being passed into the softener 25, valve 13a being closed, through the valve 26, thence through the orifice 38 of the casing 36, and past the valve 31 through the pipe. 27 into the low temperature stage B of the heat interchanger. While I have spoken of this as the low temperature stage, it is understood that the temperature of the entering blow-ofi1 water may be approximately 212 F. Heat, therefore, is rapidly transferred to the cold water, which, on passing through the pipe 28, ,make-up storage 29, Iand pastthe valves 30 and 14 into the feed Water heater 6, is boiled, thereby releasing the dissolved or suspended gases which then may pass up through the vent 6a. K

The water thus relieved of its gases. to-

gether with condensed steam returns, which enter the heater through the pipe 7 and together with the water that is condensed from the steam which enters the heater through the pipe 8, is forced by the boiler feed pump 9 through the pipe 10, into the high temperature stage A of the heat interchanger, by the pipe 23, as heretofore described. Here the water is heated to a higher temperature by the Water withdrawn from the boiler and then enters the boiler through,the pipe 10, as stated. The flow of make-up water and blowoff water is controlled automatically by the difference in pressure on the two sides of the orifice 38 in the casing 36. This casing communicates,. as stated, with a casing 56 by means of the pipes 34 and 35 in such'a manner that the pressure on opposite sides of the orifice 38 is reproduced in the casing 56 on opposite sides of the diaphragm 33. When the drop 'in pressure through theorifce grows greater, the diaphragm 33 moves to open the valves 31 and 32, which, as stated, control the inilow of the make-up Water as well as the outflow of the boiler water. When the drop in pressure through the orifice grows less, then the valves close orrrestrict their openings.

The valves 31 and 32 may also be controlled by the float 15, for itis obvious that when the ioat rises with the water which has entered the heater 6, the movement of the loat would be communicated through the rod 40, lever 41, link 42, and lever 43 to the valve, stem 39 to close the valve, while, when the E, Water lowers, it will open the valve.

The water is preferably withdrawn through pipe`22 from the bottom of settling chamber 21, where the concentration of precipitated matter is greater than the average in circulation in the boiler. The controlling of the rate of withdrawal according to the .change then the control of the rate of withdrawal according to the degree of concentration will take place. If While these other controls are functioning the discharge should become warm, then the outlet valve will reduce the rate of Withdrawal. It will thus be seen that by the means outlined there will be a minimum of water withdrawn from the boiler and a minimum of heat lost in the Withdrawn water, in maintaining automatically the concentration at a minimum desired degree.

In cases Where the utmost accuracy in the maintenance of a fixed degree of concentration is not required the concentration control can be omitted. Or if heat economy with only a moderate degree of control of the concentration is desired then the `thermostatic valveonly may be used, or if only approximate concentration control is wanted the Withdrawal and make-up streams can have their flow ratio controlled. In other words, one or more of the controls can be omitted. The controls may be of any type to accomplish the desired purpose. For example, the thermostatic valve maybe of any suitable type and may be set to operate at any suitable temperature so as to open the exit to the waste pipe at temperatures below any predetermined desired temperature, and to close the exit if the outgoing boiler water at the exit is hotter than this pre-determinedA desired temperatures. The flow of make-up water may be controlled manually by means of the by-pass valve 17.

As a specific example, the make-up water may enter the low temperature stage at about 60 F., and leave it usually at about 100 F., but may leave it at 212 F. as an upper limit. The outgoing boiler water entering the high temperature stage wouldenter at boiler temperature, which would be about 350 F. if the pressure were 125 pounds, and it would leave the high temperature stage at a temperature approaching 212 F. asa lower limit. The feed water flowing inthe opposite direction through the high temperature stage would enter at ah'out 212 F. (if the steam in the deaerator is at atmospheric pressure) and would leave the heat exchanger and enter the boiler at usually about 220 F., but may reach the boiler temperature as an upper limit, which would he about 350 F., if the pressure were "125 pounds. y'

Let us assume that the concentration of soluble salts in the water within the boiler is to be maintaine'dat 50 grains per gallon and that the make-up water contains 10 grains per gallon ofpermanentlysolublesalts. It is evident that the rate of withdrawal of Water must be at one fifth the rate of feeding make-up, because the concentration in the outgoing Water willbe five timesthatof the makeup water, and one fifth of a gallon of outgoing Water will contain the same quantity of impurity as one gallon of make-up water. It

with the same in the makeup, will be in the' same ratio as the quantity of make-up fed bears to the quantity of water withdrawn from the boiler. Thus If the boiler water f concentration is five times the concentration of the make-up, then the average quantity of make-up fed is five times the average quantity of boiler water withdrawn. This is true if all the impurities remain in the water.

If the impurities settle out of the' water in the boiler, the`concentration will be further reduced.

It will thus be seen that I haveprovided a process and apparatus by `means ofv which water in the boiler may be continually puri-x fied, first, by removing gases from the boiler feed water, and allowing of other treatment like filtering or chemical dosing in the heater, and second, by introducing to the boiler a substantial quantity of make-u water, containing a relatively small quantlty of foreign matter, in excess of that required for the replacement of boiler feed and steam circuit losses, and permanently removing a substan-l tially equal quantity of concentrated boiler water containing a relatively large amount of foreign matter. o Relatively' little heat is lost because the water discharged fromthe boiler gives up its heat to the incoming feed water and added make-up water.

The advantages of using a two stage heat interchanger are: First, it provides between the low temperaturestage and the high temperature stage an opportunity; (a) to improve the condition of the water such as'to de-aerate it, filter it, chemically treat it, settle it, etc.; (b) to join it to the condensed steam returns, which generally constitutethe main body of boiler feed water; (e) to heat .it flirther by exhaust or other waste steam, thereby conserving heat. Second, (a) the two stage arrangement provides a means whereby,v the make-up is heated to usually very much less than 212o F. in the low temperature stage, and the boiler feed water is heated to' not much higher than 212 F. in the high temper` `ond stage the withdrawn water can be cooled to approximately the same temperature as the cold make-up water; (d by cooling only.

with make-up in the secon stage an oppor- `tunity is provided to control the outgoingA boiler water by means ofthe make-up water or vice versa, that is, the rate of flow of one can be used to control the rate of flow ofthe other.

It will be understood that foreign matter `in the boiler water may be in solution or in suspension or may be in occulent or other orms. All water containing foreign matter in an of these forms is referred to as concentrate e the word concentration being used generically to indicate the presence of a comparatively large quantity of foreign matter, whether or not such matter is in solution. It' will be obvious that the method and apparatus herein `disclosed and claimed is adapted to decrease the proportion of such'foreign matter in the boiler water regardless of the form of the foreign matter and by purificater from the water regardless of its form.

Due to the fact that steam tends to form upon the surfaces of undissolved foreign matter in' the boiler water and thereby to lift such foreign matter toward the top of the boiler, the system as disclosed herein is as- `sisted in its functioning by the concentration I c a l l tion I mean the ellmination of foreign matranged to receive heat .from said heat interchanger, a make-up water line arranged to receive heat from said heat interchanger and subsequently connected with said feed water line, and means for automatically controlling the withdrawal of the water from the boiler in proportion to the rate of flow of the .make-up water.

2. The combination with a boiler, of a heatr interchan er, means for conducting water from the oiler to the'heat 'interchanger, a feed water line leading to said boiler and arranged to receive heat from said heat interceiveheat from said heat interchanger and subsequently connected with said feed water line, and means for artomatically controlling the rate of liow of make-up 'water in propor# v tion to .theiate of withdrawal-of the water from the boiler. through the heat inter-v changer. A

3. The combination of a boiler, means for withdrawing water from the boiler, a heatinterchan er, means for passing the water witho drawn om the boiler through the heat interchanger 'and `permanently and wholly discharging it unmixed with other Water, a feed v changer, a make-up water line arrangedv to re.-

water line leading to the boiler through a relatively high temperature portion of said heat interchanger, a source of condensate connected with said feed water line, a make-up water line passing through a relatively low temperature portion of said heatl interchanger and connected with saidrfeed water line in advance of the passage of said. feed water line through said interchanger, and means for controlling the How ofthe water discharged from the heat interchanger in a reverse proportion to its temperature.

4. The combination with a boiler, of means for withdrawing water from the boiler, a heat interchanger, means for passing the water withdrawn from the boiler through said heat interchanger and for discharging it, a source of makewater, means for connecting said source with) said heat interchangerfor heating the make-up water by' the water withdrawn Y from the boiler, means for introducing the heated make-up water into the boiler and means for simultaneously controlling the passage of the make-up water into the heat interchanger and the discharge of boiler water from said heat interchanger.

5. The combination with a boiler, of means for withdrawing water from the boiler, a heat interclianger,` means for passing the water withdrawn from the boiler through said heat interchanger and for discharging it, a source of make-up water, means 'for connecting said source with said heat interchanger for heating the make-up water by the water withdrawn from the boiler, a de-aerator for receiving the heated make-up Water, means for conducting the de-aerated make-up water to the boiler, a float in said de-aerator, aildmeans actuated by the ioat for simultaneously controlling the discharge of boiler water from the heat interchanger and the passage of make-up water to the heat interchanger.

6. The herein described process of purifying water within a boiler, which consists in permanently withdrawing water from the boiler, heating make-up water-by the water withdrawn from the boiler, passing said make-up water to a feed water line, diluting said make-up water in the feed water line with water substantially free of impurities, subsequently delivering to the feed water an additional quantity of heat `from water so` withdrawn and introducing the heated feed water into the boiler.

7 The herein described process of purifying water within a boiler, which consists in permanently withdrawing from the boiler water containing foreign matter in concentrated form and`replacing the water thus withdrawn by make-up water containing foreign matter in less quantities, the rate of withdrawal and replacement of boiler water with make-up as aforesaid being sufliciently rapid, taking boiler temperatures, boiler load and make-up water impurities into account,

to maintain boiler concentration below the point of substantial scale deposit while safeguarding against undue waste of boiler water after having attained said point of concentration.'

8. The herein described process of purifying water within a boiler, which consists in permanently and wholly withdrawing water rom the boiler, heating previously unheated make-up water by the water withdrawn from the boiler, storing the heated make-up water for the separation of impurities therefrom, passing said make-up water to a feed water line, subsequently heating the feed water, by means of the water withdrawn from the boiler, and introducing the heated feed water into the boiler.

9. The combination of a boiler, a blow-oii' line leading therefrom, a chamber connected with said blow-olf line for concentrating impurities, said blowoif line leading from a portion of said chamber in which foreign matter is adapted to collect, and a return conduit connecting said boiler with a portion of said chamber adapted to contain water from which impuritieshave settled, whereby to permit the circulation back to said boiler of partially deconcentrated water, a boiler feed line, a make-up water line leading thereto, means for cooling blow-off water containing substantially all of its boiler derived heat in said blow-oftl water line with water passing to lthe boiler .through said make-up and feed water lines, While keeping the blow-olf water at pressures above the ash point during its cooling whereby to return to the boiler substantially all heat of water withdrawn through aI portion of said chamber in which the impurities have been concentrated, and means for wholly and permanently discharging the cooled blow-off concentrate so withdrawn.

10. The herein described process of deconcentrating boiler water without substantial heat losses, which consists in withdrawing relatively concentrated water from the boiler, prelilninarily cooling said water and imparting the heat derived'therefrom to the boiler feed, then further delivering heat from said withdrawn water while it is under pressures materially 'in excess of atmospheric to a quantity of undiluted make-up water, feeding the heated make-up water to the boiler, and wholly discharging substantially all the Y cooled water so withdrawn.

11. The herein described process of deconcentrating' boiler water without substantial heat losses, which consists in withdrawing relatively concentrated water from the boiler, preliminarily cooling said water and imparting the heat derived therefrom to the boiler feed, then further delivering heat from said withdrawn water while it is under pressures materially in excess of atmospheric to a quantity of undiluted make-up water, exposing the ly discharging substantially all the cooled water so withdrawn.

12.v The herein described rocess'of deconthe boiler.

., 16. 'The combination' a valve controlled, blow-off pipe' communicatd ing with said .boilerand terminatingffor the water tothe high 'stageof-the l, heat-interchanger, means for delivering the'' water from the highfemperature ,stage into centrating boiler water,"w ich consists in` permanent dischar therethrough of blow?l` adding tokthe return feed water a quantity of make-up watermaterially in excess of replacements required for'lossesx in the boiler l ',stiiliciently in excess of boilersystem losses to replgceithe amount ofconcentratedwater so withdrawn, cooling the withdrawn boiler water prior to its comminglin Water and steam system, withdrawing a quantity of concentrated boiler water substantiallyl equal toi the excess. quantity of make-up water, delivering heat from the water so withdrawn rst tothe `feed water and secondly tothe make-up water, and permanentldydischarging the cooled water sofwithrawn. 'i

13. The herein described processvfor deconcentratingV boiler Water wlthout substantial heat losses, 'which consists in withdrawing.

from the boiler a quantity of concentrated water, collecting condensate for delivery to the boiler, adding to the condensate to conv4 prise feed water aquantity of'make-up Water water approximately to the atmospheric boil` ing point by'deliver7 lof yheat therefrom to the boiler feed.' water, further cooling the withdrawn water by heating'the Vmake-up condensate for driving gas there rom, expos-v ing the make-up water to substantially. at-

' mosph'eric pressure to permit the escapeof such gas, and permanently dischar g thel off vwater issuing ,om said" p ipe of aheat interchanger communicating: wlthfsaidpipe for ,the passage therethrough J'of :blow-oil. watertraversi said pipe, meansifor su plying said boi er withfwater'fthrough-sald eat interchanger, whereby the lwater so suplplied vwill. derive heatfrom said blow-off water, means Afor collecting imprities inthe output of said boiler for delivery without inter ering with the discharge of boiler water through saidpipe, andautomatically o erable valveactuating mechanism operative y -connected with sald blow-'off valve and respon- )sive to water carr ing the impurities co1- lected as aforesai from said boiler is in genera .pro ortion to the collection of impurities in t e output thereof. v l

17. The combination with a boiler and a heatint'erchanging device operatively connected bya blow-ofi' pipe with said boiler and` with saidfthe stages of said 'interchanger, and a make- Jup water line leading. through the other stage of said interchanger to said feed water line and conn'ected'therewith prior to its passage through said interchanger, whereby whereb the blow-off4 cooled and relatively concentrate boiler make-up Water heated in one stage of said. water so withdrawn.l h, i j l y interchanger will be commingled with relam5 14. The herein described method of deconf tively pure Water in said feed water line becentrating boiler water, which consists i thev partial heating of raw make-up Water by means of concentrated water withdrawn from the boiler, the dilution of the partially heated make-up water with condensate boiler return f feed water, the yfurther heating of thermixture of make-up and feed water, and `the permanent blow-ofi:I of allf'the concentrated boiler water so withdrawn.

15. The combination with a boiler of a heat interchanger having a high temperature stage and a low temperature stage, means for withdrawing Water from the boiler and delivering it to the high temperature stage,-

means for delivering the said withdrawn boiler water from the high temperature stage i .to the 10W temperature stage, a source of make-up water, means for delivering makef up water from said source to the lowv temperature st gef of the heat interchanger, means for di utin-g partially heated make-up water with substantially pure water upon its delivery from the low temperature stage of the-'Vinterchanger and conveying the diluted water line passing through the low temperature stage of said interchanger and connected with said feed water line prior to its passage through said high temperature stage, a boiler steam pipe system including return lines for supplying condensate to said feed water line, and means for feeding raw water to said make-up water vline whereby said raw water will be moderatel heated in the low temperature stage of saidyinterchanger, diluted with condensate, and subsequentlyheated to a relatively higher temperature in said interchanger to conserve the heat of the blow-oif without precipitation in the interchanger. v

19. The combination with a boiler and a f said interchanger to said boiler, a make-up 115V source of condensate, of a feed water line leading to said boiler and connected with said source to receive condensate therefrom, a blow-off line leading from said boiler for the permanent discharge of boiler water therefrom and including a heat interchanger having a plurality of stages through one of which saidffeed water line passes, a make-up water line passing through another of said stages, a tank into which said make-up water line discharges and a pipe from said tank to said feed water line for delivering makeup water into the condensate in advance of its passage through said heat interchanger, whereby raw make-up water is partially heated by blow-off Water, is partially purified in said tank, is diluted by condensate and subsequently additionally heated by blow-off water before delivery into said boiler.

20. The combinat on with a boiler and a boiler steam pipe system, including condensate returns, of a boiler blow-off pipe adapted for the permanent discharge of boiler water and provided in the course of said water with a heat interchanging device having a high temperature stage and a low temperature stage, a feed water line passing through the high temperature stage of said interchanger to receive heat therefrom and communicating with said boiler and with said condensate returns, a make-up water line passing through the lo`w temperature stage of said heat interchanger'l to receive heat therefrom, and a vented tank affording communication be-,

leading therefrom, a make-up water pipe leading thereto, a heat interchanger connected with said pipes for the operative delivery of heat from blow-ofi' water to make-up water, a source of make-up Water supply, means connecting said source with said make-up Water pipe including a pump for the make-up water, a valve controlling the passage of blow-oft Water through said blow-off water line, and means for closing said valve when the amount of make-up water delivered by said pump to the make-up water pipe is less than the amount of make-up Water supplied to said pump from said source.

22. A boiler blow-oill system comprising the combination Wth a boiler, a blow-eff line leading therefrom, a make-up water line lleading thereto anda heat interchanger operatively connected with said lines for the delivery of blow-off water heat to the makeup water, of means for feeding make-up water through its said line, a valve controlling the flow of make-up water through its said line, a valve controlling the passage of blow-off water through the blow-Offl water line, and means for moving said last menmaeais y up water to the boiler in quantities'suflicient I to replace losses, withdrawing relatively concentrated boiler'water from the boiler, replacing the water so Withdrawn with additional make-up water in such quantities and at such intervals as to maintain the foreign content of thewater in theboiler at a concentration sufliciently low to substantially prevent scale formation and chemical decomposition, the rate of replacement depending upon the character of the make-up, preliminarily cooling the withdrawn boiler Water by the boiler feed, then delivering heat from the Withdrawn boiler water to the make-up in sufficient quantities to reduce the withdrawn boiler water almost to the initial temperature of the make-up while maintaining the withdrawn water under pressure whereby to avoid loss of latent heat, and permanently discharging the cooled and replaced water so withdrawn.

24. The process of preventing boiler scale deposits which consists in replacing relatively concentrated 4boiler water with make-up water containing impurities in less degree, the quantity of make-up so added being in excess of that required to compensate for losses, delivering from the said boiler Water to the make-up water substantially all boilerderived heat remaining in the Water to be replaced, and permanently discharging the replaced Water, the rate of replacement being substantially that required to maintain the boiler Water suiciently low in concentration to substantially prevent scale deposits while avoiding loss of Aheat by excessive withdrawals.

25. The process of preventing boiler scale deposits which consists in replacing relatively concentrated boiler Water with make-up Water containing impurities in less degree, the quantity of make-up so added being in excess of that required to compensate for losses, partially cooling with Warm boiler feed water the hot boiler water to be rel'ilaced, then dclii-*ering from the said boiler Water to the make-up water substantially all boilerderived heat remaining in the water to be replaced, and permanently discharging the replaced water, the rate of replacement being such as to maintain the boiler water suliiciently low in concentration to substantially prevent scale deposits.

26. The method of deconcentrating boiler water which consists in the partial heating of raw make-np Water by means oi concentrated water withdrawn from the boiler, and exposure ot' the partially heated make-up water to ten'iperatnres and pressures at which gases will #discharge therefrom, the dilution of the partially heated and de-aerated make-up water with condensate boiler return feed water, the further heating of the mixture of make-up water and feed water, the delivery thereof to the boiler, and the permanent blo\v-oii' of all of the concentrated boiler water so withdrawn.

27'. The method of maintaining vboiler water concentration at a predetermined low value which consists in supplying to the boiler a quantity of make-up waterin excess of that required to replace boiler system losses and withdrawing and permanently discharging rom the boiler a quantity ot' relatively concentrated boiler water suiiiciently large to removefrom the boiler substantially the amount of impurities entering the boiler in said make-up water, Vand maintaining the aforesaid withdrawal of impurities at substantially the rate at which impurities enter the boiler.

28. The process or" preventing boiler scale which consists in withdrawing and replacing boiler water with make-up water at such a rate as to maintain the impurities in the water in the boiler continuously below the degree of concentration at which scale forms, the makeup water being added in quantities sufliciently" in excess of boiler system losses to compensate for all boiler system withdrawals, and the boiler system withdrawals being effected at such a rate as to remove in the form of concentrated boiler Water substantially the same amount of impurities as are entering theboiler in thetotal quantity of make-up water added. r

29. The process of maintainingl boiler l Water at a low degree of concentration which consists in blowing oi water .from the boiler,

adding make-up water to the boiler,4 and regulating the amount of water blown ofi so that it is increased or decreased in proportion to the increase or decrease in the amount of malte-up water added.

added to the boiler.

31. A device for (le-concentrating boiler water comprising the combination with a boilerland a boiler blow-oft system, of means for adding make-up water to the boiler and a How responsive device operatively associated with said means andprovided with a regulatory valve insaid system to which said device is connected for the regulation of boiler blowoft' in accordance with make-up flow in said means.

32. The combination of a boiler and Aa source of make-up water supply, of a heat interchanger, means for withdrawing water from the boiler and delivering it into a portion of said heat interchanger at substantially boiler pressure, means for delivering previously unheated make-up water from said supply to another portion of said heat interchanger, means for permanently and wholly discharging from the boiler system all of the water so withdrawn from the boilefr, means for charging the boiler with the heated Water from/said water supply, and means for automatically proportioning the rate of withdrawal of boiler water according to the rate of adding make-up water to the boiler system.

33. The process of deconcentrating boiler Water which consists in supplying to the boiler make-up water of less concentration than the boiler water in quantities in excess of boiler system losses, wholly and permanently withdrawing from the boiler a quantity of boiler water, preliminarily cooling the withdrawn boiler water by the boiler feed, further delivering the heat of the boiler water so withdrawn to the make-up water supplied to the boiler, and thermostatically controlling the withdrawal of the boiler water. V

34;. The process of deconcentrating boiler water which consists in supplying to the boiler make-up water of less concentration than the boiler water in quantities in excess of boiler system losses, withdrawing a quantity of concentrated water from the boiler, partially cooling the water so withdrawn with boiler feed water including condensate returns, additionally cooling water thus withdrawn with the make-up water supplied to the boiler as aforesaid and controlling the rateof withdrawal of water from the boiler thermostaticall'y in inverse proportion to its temperature, whereby the quantity of blowo' water discharged is proportioned to the quantity of make-up water supplied.

35. The combination with a boiler,`of a heat interchanger having a high temperature stage and a low temperature stage, connections between the boiler and the high temperature stage of the heat interchanger, for delivering water from the boiler to the heat interchanger, a water softener, means for' delivering make-up water to said water softener, connections for delivering water from the softener to the low temperature stage of Y the heat interchanger, a de-aerator, connections for conveying water from the low temperature stage to the de-aerator, a pump, connections leading from the de-aerator to the pump, connections from the pump to the high temperature stage of the heat interchanger, and connections from said hi h temperature stage for delivering the fee water into the boiler.

36. The combination with a boiler, of a heat interchanger having a high temperature stage and a low temperature stage, means for withdrawing Water from the boiler and delivering it under substantially boiler pressure to the high temperature stage, means for delivering the said withdrawn boiler water at substantially boiler pressure from the high temperature stage to the low temperature stage, means for automatically increasing or decreasing the rate of Withdrawal of boiler water according to the rate of adding make-up Water to the system, means for permanently and wholly discharging the said Withdrawn boiler water from the system, a water soften-y er, means for delivering previously unheated make-up water to said-water softener, means for delivering make-up water from the softener to the low temperature stage of the heat interchanger, a de-aerator, means for conveying make-up water from the low temperature stage to the de-aerator, a pump, means for delivering boiler feed Water from'the de -aerator to the pump, means for delivering boiler'feed water from thepump to the high tempera- `ture stage of the heat interchanger, and means for delivering boiler feed water from the high temperature stage into the boiler, said heat interchanger being arranged to prevent the mixing of the withdrawn boiler Water with the make-up water.

37. The combination with a boiler, of a heat interchanger having a high temperature stage and a low temperature stage, means for withdrawing water from the boiler and delivering it at a pressure above its boiling point to the high temperature stage, means for delivering the said withdrawn boiler Water at a pressure above its boiling point from the high temperaturestage to the low temperature stage, means for permanently and Wholly discharging the said Withdrawn boiler water from the system, a Watersoftener, ymeans for delivering previously unheated make-up water to said water softener, meansv with the boiler feed Water and said make-up Water. l

38. The method of conditioning water in boile'rI systems consisting of a softening treatment of make-up Water, heating the treated make-up Water, introducing the heated makeup water to the boiler system, and discharging concentrated water from the boiler system and automatically proportioning the discharge of Water from the boiler system to the rate of admission of treated make-up water to the system. Y

39. The method of conditioning boiler water, which consists in withdrawing water from the boiler, returning to the boiler a relatively less concentrated port-ion of the water so withdrawn, permanently discharging from the boiler system a relatively more concentrated portion of the Water so Withdrawn, introducing make-up water to the boiler system at a rate in excess of boiler s stem losses and proportioning the rate of ischarge of relatively more concentrated boiler Water from the system to the rate of admission of make-up water to the system inversely in the ratio of the relative concentration of the discharged boiler water to the concentration of the make-up water whereby to maintain boiler Water concentration substantially constant in the system.

40. The method of conditionin Water for boiler systems, consisting in chemicall treating raw make-up water and delivering the treated make-up water to the boiler system, discharging a portion of relatively concentrated boiler water from the boiler system and automatically proportioning the discharge of concentrated Water from the system to the supply of chemically treated make-up water approximately in inverse ratio to the concentration of the Water withdrawn with respect to the water added, whereby to maintain a substantially constant concentration of water in the boiler system.

4l. The process of maintaining boiler water at a low degree of concentration which consists in blowing off water from the boiler, adding make-up water to the boiler, and vmechanically proportioning the rate of blowing oi boiler water to the rate of introducing make-up water in a ratio approximately inverse to the concentration ofthe withdrawn boiler water with respect to the make-up Water, whereby the discharge of salts from the' boiler will at least equalA the rate of introductionv of salts thereto.

ROY O. HENSZEY. 

